Genetically modified plants sniff out explosives

Colorado State University Biologist Rewires Plants to Detect Pollutants, ExplosivesColorado State University

Biologists at Colorado State University are getting the
attention of DARPA and the US Department of Homeland Security with
a genetically
modified plant that turns white when it detects dangerous
chemicals in the air.

It is suggested that shopping malls and airports could be
lined with luscious green flora, that are suddenly drained of
colour if a harmful pollutant or explosive chemical is detected
nearby. "If a bad guy walks by with explosives in their bags at the
airport, our plants can detect that," says Colorado State
University's June Medford.

To perform this genetic modification, the university's Baker and Hellinga
laboratories had to tweak some of the plant's most fundamental
engineering.

Plants have naturally occurring proteins called receptors,
lodged in their cell wall that tell the plant what's going on around them. If those receptors sense
light or an aggressive insect, it can trigger an appropriate
response to move towards the sun or defend itself from the bug.
"Plants can't run or hide from threats, so they've developed
sophisticated systems to detect and respond to their environment," Medford says.

Medford and her team used a computer program to write
custom-designed receptors that specifically recognise a single
pollutant or explosive, and then tell the plant to lose its green
hue if it detects that chemical. "We've 'taught' plants how to
detect things we're interested in and respond in a way anyone can
see, to tell us there is something nasty around," explains Medford.
The manipulated receptors are then targeted at the plant's cell
wall, and binds them with the plant's DNA.

Right now, the plant can sniff out trinitrotoluene (TNT) in
a few hours, slowly turning to green when in the presence of the
explosive. Over the next few years, the team plans to speed up the
detection time to a matter of minutes.

The bomb-sniffing plants have piqued the interest of several
defense and research companies, with firms like DARPA, the Office of Naval Research, the National Science
Foundation and Department of Homeland Security Science all pitching
in with funding. Medford's results have been published in the journal PLoS One.